Tsunami (December 26) - Waves of Tears
On Sunday, December 26, 2004, a significant earthquake occurred off the western coast of Indonesia's Sumatra Island. The powerful earthquake then triggered a tsunami that radiated-out across the Indian Ocean for almost two thousand miles. Hardest hit were Phuket Island, Thailand, the southern coastlines of Sri Lanka, Indonesia and India. As the series of waves continued west, they lightened in intensity, but reached the Maldives, Seychelles, and the eastern coastlines of Madagascar and Somalia in Africa.
A tsunami is a series of waves generated in an ocean or other body of water by a disturbance such as an earthquake, landslide, volcanic eruption, or meteorite impact. The picture at the left shows how an earthquake can generate a tsunami in the overlying water. Undersea earthquakes, which typically occur at boundaries between Earth's tectonic plates, cause the water above to be moved up or down. Tsunami waves are formed as the displaced water, hich acts under the influence of gravity, attempts to find a stable position again. Undersea landslides, which can be caused by large earthquakes, can also cause tsunami waves to form as water attempts to find a stable position.
The Tsunami in the Indian Ocean triggered by the most powerful earthquake on Earth in 40 years generated the largest Tsunami in the Indian Ocean since 1883. Some of the tsunamis reached as far as 3,000 miles from the epicenter of the 9.0 magnitude quake, which was located about 100 miles (160 km) off the coast of Indonesia's Sumatra Island at a depth of about 6.2 miles (10 km). The death toll will likely be in excess of 150,000 and the damage though restricted to the immediate coastal area is unparalleled. The earthquake, whose magnitude was a staggering 9.0, unleashed walls of water more than 10 meters high.
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The regions has been struck by numerous aftershocks-note the table and map below. Much like a zipper the quakes initially progressed north along the fault to the Andaman Island Region. A tsunami is not a single wave, but a series of traveling ocean waves generated by geological disturbances near or below the ocean floor. With nothing to stop them, these waves race across the ocean until they reach shore where they slow down and rise up in height. Most tsunamis are triggered by large undersea earthquakes but they can be caused by landslides, volcanoes or even meteor impacts. The last large tsunami in the region was due to the eruption of Krakatoa in 1883, due to the collapse of that volcano during an explosive eruption. In this case the ocean bottom shifted displacing sea water in the ocean basin. The bigger the earthquake, the more the Earth's crust shifts and the more seawater begins to move. A quake of this magnitude typically shifts the earth surface by up to 10-20 meters. In this case the rupture was up to 400 miles long, leading to a massive region of the ocean bottom shifting. The waves traveled outward just like those from throwing a rock into the water. Most tsunamis occur in the Pacific because the ocean basin is rimmed by the Ring of Fire, a long chain of the Earth's most seismically active spots.
It was felt by fourteen countries in the region surrounding the Indian Ocean. It is said that the tsunami 2004 was not the result of one single tsunami, but the 2004 tsunami was the result of several tsunamis that had occurred in the area. An earthquake is said to have reflected the several tsunamis that had erupted throughout the region. From there, the domino effect seemed to have occurred in the surrounding area from earthquakes to tsunamis erupting as a chain reaction to the initial damage. Even the aftershock of the tsunami 2004, caused a horrible effect on the region.
some drops of tears.....
On Sunday, December 26, 2004, a significant earthquake occurred off the western coast of Indonesia's Sumatra Island. The powerful earthquake then triggered a tsunami that radiated-out across the Indian Ocean for almost two thousand miles. Hardest hit were Phuket Island, Thailand, the southern coastlines of Sri Lanka, Indonesia and India. As the series of waves continued west, they lightened in intensity, but reached the Maldives, Seychelles, and the eastern coastlines of Madagascar and Somalia in Africa.Tsunamis, also called seismic sea waves or, incorrectly, tidal waves, generally are caused by earthquakes, less commonly by submarine landslides, infrequently by submarine volcanic eruptions and very rarely by a large meteorite impact in the ocean. Submarine volcanic eruptions have the potential to produce truly awesome tsunami waves. The Great Krakatau Volcanic Eruption of 1883 generated giant waves reaching heights of 125 feet above sea-level, killing thousands of people and wiping out numerous coastal villages.
Undersea volcano eruptions can create enough force to uplift the water column and generate a tsunami. Asteroid impacts disturb the water from above, as momentum from falling debris is transferred to the water into which the debris falls.
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The regions has been struck by numerous aftershocks-note the table and map below. Much like a zipper the quakes initially progressed north along the fault to the Andaman Island Region. A tsunami is not a single wave, but a series of traveling ocean waves generated by geological disturbances near or below the ocean floor. With nothing to stop them, these waves race across the ocean until they reach shore where they slow down and rise up in height. Most tsunamis are triggered by large undersea earthquakes but they can be caused by landslides, volcanoes or even meteor impacts. The last large tsunami in the region was due to the eruption of Krakatoa in 1883, due to the collapse of that volcano during an explosive eruption. In this case the ocean bottom shifted displacing sea water in the ocean basin. The bigger the earthquake, the more the Earth's crust shifts and the more seawater begins to move. A quake of this magnitude typically shifts the earth surface by up to 10-20 meters. In this case the rupture was up to 400 miles long, leading to a massive region of the ocean bottom shifting. The waves traveled outward just like those from throwing a rock into the water. Most tsunamis occur in the Pacific because the ocean basin is rimmed by the Ring of Fire, a long chain of the Earth's most seismically active spots. In a tsunami, waves typically radiate out in directions opposite from the seismic disturbance. In the case of the Sumatra quake, the seismic fault ran north to south beneath the ocean floor, while the tsunami waves traveled mainly west and east. Tsunamis are distinguished from normal coastal surf by their great length, width and speed. Not all earthquakes generate Tsunamis. To generate tsunamis, earthquakes must occur underneath or near the ocean, be large and create movements in the sea floor. All oceanic regions of the world can experience tsunamis, but in the Pacific Ocean there is a much more frequent occurrence of large, destructive tsunamis because of the many large earthquakes along the margins of the Pacific Ocean. A single wave in a tsunami series might be 100 miles long and race across the ocean at 600 mph. When it approaches a coastline, the wave slows dramatically, but it also rises to great heights because the enormous volume of water piles up in shallow coastal bays. Unlike ordinary waves tsunamis do not break on the coastline every few seconds. Because of their size, it might take an hour for another one to arrive. There unusual speed and wavelength allows tsunamis to be identified by buoys moored in the ocean. Although seismic networks recorded Sunday's massive earthquake, there were no wave sensors in the Indian Ocean region and no means to determine the existence or direction a tsunami would travel. Thus, no warnings were issued.
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A single wave station south of the earthquake's epicenter registered tsunami activity less than 2 feet high heading south toward Australia, researchers said. The Pacific Ocean does have a Tsunami warning system. The international warning system was started in 1965, the year after tsunamis associated with a magnitude 9.2 temblor struck Alaska in 1964. It is administered by the U.S. National Oceanic and Atmospheric Administration. Member states include all the major Pacific Rim nations in North America, Asia and South America was well as the Pacific islands, Australia and New Zealand. However, India and Sri Lanka are not members because tsunamis are not common in the Indian Ocean and the instruments are expensive. Both of these nations would have had several hours of time to respond to a warning, to evacuate coastal areas. It would be surprising if a
network was not put in place now. Such a system would not have helped Indonesia since it was so close to the epicenter that the waves would strike very quickly. Many would argue that the damage that the tsunami 2004 caused to the region was larger than life.
It was said to be caused as a result of the one of the tectonic plates of the Indian Ocean being merged under another. This in turn, caused the tectonic plates to sink into the earth’s mantle. This process by which the 2004 tsunami resulted is called subduction. The subduction did not occur over night in order to cause the 2004 tsunami. The tsunami 2004 was formed after the tectonic plates began to use their original disposition. The annual rate for which the tectonic plates began to move out of order is at a rate of 2 to 8 centimeters each year.
The death toll for the 2004 tsunami was one of the highest ever death occurrences of one population to result out of a single incident. The tsunami 2004 took the life of almost 230,000 people. The tsunami 2004 had a tremendous effect on fourteen countries in the area, total. The 2004 tsunami had caused the most damage to the countries of Indonesia, Thailand, Sri Lanka, and India.
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